Timed Automata Semantics for Analyzing Creol

We give a real-time semantics for the concurrent, object-oriented modeling language Creol, by mapping Creol processes to a network of timed automata. We can use our semantics to verify real time properties of Creol objects, in particular to see whether processes can be scheduled correctly and meet their end-to-end deadlines. Real-time Creol can be useful for analyzing, for instance, abstract models of multi-core embedded systems. We show how analysis can be done in Uppaal.Comment: In Proceedings FOCLASA 2010, arXiv:1007.499

Do Null-Type Mutation Operators Help Prevent Null-Type Faults?

The null-type is a major source of faults in Java programs, and its overuse has a severe impact on software maintenance. Unfortunately traditional mutation testing operators do not cover null-type faults by default, hence cannot be used as a preventive measure. We address this problem by designing four new mutation operators which model null-type faults explicitly. We show how these mutation operators are capable of revealing the missing tests, and we demonstrate that these mutation operators are useful in practice. For the latter, we analyze the test suites of 15 open-source projects to describe the trade-offs related to the adoption of these operators to strengthen the test suite

Relating Session Types and Behavioural Contracts: The Asynchronous Case

We discuss the relationship between session types and behavioural contracts under the assumption that processes communicate asynchronously. We show the existence of a fully abstract interpretation of session types into a fragment of contracts, that maps session subtyping into binary compliance-preserving contract refinement. In this way, the recent undecidability result for asynchronous session subtyping can be used to obtain an original undecidability result for asynchronous contract refinement

SIP: Optimal Product Selection from Feature Models Using Many-Objective Evolutionary Optimization

A feature model specifies the sets of features that define valid products in a software product line. Recent work has considered the problem of choosing optimal products from a feature model based on a set of user preferences, with this being represented as a many-objective optimization problem. This problem has been found to be difficult for a purely search-based approach, leading to classical many-objective optimization algorithms being enhanced either by adding in a valid product as a seed or by introducing additional mutation and replacement operators that use an SAT solver. In this article, we instead enhance the search in two ways: by providing a novel representation and by optimizing first on the number of constraints that hold and only then on the other objectives. In the evaluation, we also used feature models with realistic attributes, in contrast to previous work that used randomly generated attribute values. The results of experiments were promising, with the proposed (SIP) method returning valid products with six published feature models and a randomly generated feature model with 10,000 features. For the model with 10,000 features, the search took only a few minutes.CICYT TIN2012-32273CICYT TIN2015-70560-RJunta de Andalucía TIC-5906Junta de Andalucía P12-TIC- 186

Flexible Process Notations for Cross-organizational Case Management Systems

In recent times western economies have become increasingly focussed on knowl-edge work. Knowledge work processes depend heavily on the expert knowledge of workers and therefore tend to require more flexibility then the processes seen in traditional production work. Over-constrained processes cause frustration and inefficiency because they do not allow workers to use their expert experience to make the best judgements on how to solve the unique challenges they are faced with. However some structuring of their work is still required to en-sure that laws and business rules are being followed. IT Systems for process control have a large role to play in structuring and organizing such processes, however most of these systems have been developed with a focus on produc-tion work and fail to support the more flexible processes required by knowledge workers. The problem arises at the core of these systems: the notations in which the processes are defined. Traditional process notations are flow-based: control of the process flows from one activity to the next. This paradigm in

Enabling Multi-Perspective Business Process Compliance

A particular challenge for any enterprise is to ensure that its business processes conform with compliance rules, i.e., semantic constraints on the multiple perspectives of the business processes. Compliance rules stem, for example, from legal regulations, corporate best practices, domain-specific guidelines, and industrial standards. In general, compliance rules are multi-perspective, i.e., they not only restrict the process behavior (i.e. control flow), but may refer to other process perspectives (e.g. time, data, and resources) and the interactions (i.e. message exchanges) of a business process with other processes as well. The aim of this thesis is to improve the specification and verification of multi-perspective process compliance based on three contributions: 1. The extended Compliance Rule Graph (eCRG) language, which enables the visual modeling of multi-perspective compliance rules. Besides control flow, the latter may refer to the time, data, resource, and interaction perspectives of a business process. 2. A framework for multi-perspective monitoring of the compliance of running processes with a given set of eCRG compliance rules. 3. Techniques for verifying business process compliance with respect to the interaction perspective. In particular, we consider compliance verification for cross-organizational business processes, for which solely incomplete process knowledge is available. All contributions were thoroughly evaluated through proof-of-concept prototypes, case studies, empirical studies, and systematic comparisons with related works

Passive Testing of Stochastic Timed Systems

In this paper we introduce a formal Methodology to perforin passive testing, based on invariants, for systems where the passing of time is represented in probabilistic terms by means of probability distributions functions. In our approach, invariants express the fact that each time the implementation under test performs a given sequence of actions, then it must exhibit a behavior according to the probability distribution functions reflected it? the invariant. We present algorithms to decide the correctness of the proposed invariants with respect to a given specification. Once we know that an invariant is correct, we check whether the execution traces observed from the implementation respect the invariant. In addition to the theoretical framework we have developed a tool., called PASTE, that helps in the automation of our passive testing approach. We have used the tool to obtain experimental results front the application of our methodology